Ignition and control system for fuel burners



y 1954 w. s. KUNZLER ETAL 2,679,560

TROL SYSTEM FOR FUEL BURNERS IGNITION AND CON Filed Dec. 30, 1948 2 Sheets-Sheet 1 'INVENTORS "221mm 5. Kmzlep tZ/Id y William JECZSSGIZ.

THE/ grrolzzvziy 2 Sheets-Sheet 2 w. s, KUNZLER ET AL IGNITION AND CONTROL SYSTEM FOR FUEL BURNERS (am Jkassell.

INVENTORS .fifialzzlep and W266 7 /1510 wroggvli mzazm Q NR E Q @m A 3 a SQ g m Q Q \NN TE vi m k v a H mm May 25, 1954 -Fi led Dec. 30, 1948 NW VN Patented May 25, 1954 IGNITION AND CONTROL SYSTEM FOR FUEL BURNERS William S. Kunzler, Greensburg,

Russell, Jeannette, Pa. assignors to Robertshaw-Fulton Controls Company, Greensburg, Pa., a corporation of Delaware Application December 30, 1948, Serial No. 68,338

3 Claims.

This invention relates to control and ignition systems for fuel burners and, more particularly, to combined thermoelectric pilot control and electric ignition apparatus for domestic gas ranges.

Electric ignition by hot wire coils for gas burners usually involves electrical connections through step-down transformers to commerical sources of current supply. The voltage from such sources may vary considerably with standard transformers and seriously limit the life of the igniter coil. Moreover, as the igniter is required only for limited periods during range operation, it is unnecessarily wasteful to maintain any part of the electrical system in energized condition beyond such limited periods.

An object of this invention is to obtain reliable igniter performance over a wide range of voltage fluctuations while also extending the useful life of the igniter.

Another object of the invention is to completely deenergize the igniter circuit as soon as the gas burner produces a flame.

Another object of the invention is to secure complete shut-01f of fuel to both main and pilot burners in a range compartment upon operation of the automatic pilot device.

Another object of the invention is to control the automatic pilot device by the customary manipulation of the main shut-off valve.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings wherein:

Fig. 1 is a schematic view of a control and ignition system embodying the invention,

Fig. 2 is a longitudinal sectional view through the control device of this invention,

Fig. 3 is a fragmentary plan view of the handle or knob portion of the control device,

Fig. 4 is a crosssection taken on the line IV IV of Fig. 2,

Fig. 5 is a cross section taken on the line VV of Fig. 2 and Fig. 6 is a cross-section taken on the line VI- VI of Fig. 2.

Referring more particularly to Fig. 1 of the drawings, a main fuel burner ill is supplied with fuel from a manifold 12 by way of a main fuel gas cook l6 carried by Interposed in the main fuel supply pipe M between the gas cock I 6 and the main burner I0 is a control device designated generally by the reference numeral H3. The construction of the control device 18 is shown more clearly in Figs. 2 to 6 inclusive and includes a tubular body member 28 provided with an internal annular valve seat 22 interrupting the contour of the flow passage through the tubular body member at a point substantially midway between the ends.

winding and armature (not The electromagnetic device 24 is operable to retain a fuel control means or valve member 26 carried thereby in spaced arrangement with one side of the valve seat 22 when the electromagnet is energized and to permit the valve member 2t to engage the valve seat 22 under bias of a spring 28 when the electromagnet is deenergized. The opposite end of the electromagnet device projects from the tubular member I B and carries the usual terminal connector 30 through which the leads 32, 34 for the magnet winding are carried.

The tubular member 20 is provided with a plurality of ports 36 extending through the wall thereof on either side of the valve seat 22. Any number of ports may be utilized and spaced cirto provide different degrees of adjustment for a pair of connecting members 38. Each of the members 38 has an annular portion 40 and a hollow end embodiment, the connecting means t2 on the lefthand side of the valve seat 22, as viewed in Fig. 2 of the drawings, provides an inlet connection for the fuel pipe l4 while the connecting means 42 on the right-hand side of the valve seat 22 provides an outlet connection therefor.

The annular portion 42 of each connecting of the ports as previously indicated. When such alignment has occurred, each annular portion is clamped in engagement with opposite faces respectively of an external annular abutbe more fully the abutment 46 form oppositely disposed seats for each annular portion 40 and a pair of packing rings 43 may be interposed between these abutting end faces for sealing against leakage.

members 54 and 56 Each of the connecting members may be provided with means for mounting the control device in a selected location at the point of use. Thus, a lug 50 projects transversely from the annular portion 40 of each connecting member opposite the hollow end portion 42. The lug 50 is approximately equal to the width of the annular portion 4c across the end faces thereof and is relatively shallow in thickness. A perforation 52 is provided in the lug 50 for the reception of a bolt, screw or other securing means when the device is installed.

The connecting members are secured in the selected position by means movable relatively to the tubular member 20 from opposite ends thereof. This means takes the form of end cap which may be generally similar in form except as necessarily modified by the particular structure of the control device. In this embodiment, the end cap 54, which is located at that end of the tubular member 20 having the electromagnetic device 24, is provided with internal threads 58 which engage complemental threads on the tubular member 20 for securing the connecting member in position. The end cap 54 is suitably flanged to extend partly around the electromagnetic device 24 and through which the terminal connector 30 projects. The terminal connector 30 is threaded for engagement by a nut 60 which abuts the flanged end of the end cap 54 and serves to secure the electromagnetic device 24 against endwise movement.

The end cap 56 at the opposite end of the control device I8 also has an internal threaded end 62 engaging a complemental threaded end of the tubular member 20. In addition, this end cap 56 is provided with a threaded bore 64 which engages a threaded portion of a reset housing 66 and serves to secure it in position in the cap 56 by provision of a flanged end 68, which engages the end of the reset housing 66. A second pair of packing rings 10 may be provided between the abutting faces of the end caps 54 or B and the annular portion 40 of each of the connecting members these points.

The reset housing 66 is suitably apertured at one end for slidable engagement with a reset stem I2 which projects exteriorly therefrom and carries an extension rod 14 on its inner end projecting toward the valve member 25. A second valve member 16 is carried on the projecting end of the extension rod 14 and is adapted to engage the opposite side of the valve seat 22 from that engaged by the valve member 26. Such engagement occurs when reciprocation of the reset stem I2 takes place and it is desired that the flow of fuel past the valve seat 22 be interrupted during the resetting operation when the main valve member 26 is moved off its seat. Such movement is effected by the valve member 26 being engageable by a cap nut 18 carried on the end of the extension rod 14 but which is normally spaced from the valve member 26.

The flow interrupter valve member 16 is biased away from the valve seat 22 by a coil spring 85 which is operative between the reset stem 12 and a packing ring 82 for the extension rod "M. A second packing ring 84, secured on the end of the housing 66, is adapted to be engaged by the flow interrupter IS in its biased position and serves as an additional shield against leakage along the rod I4. A second coil spring 86 is operative between the flow interrupter valve iii and the housing 66 for biasing the valve I6 toward to seal against leakage at ,1

the cap nut 18. It will be apparent, however, that the coil spring is stronger than the coil spring 86 in order that the described biased position of the flow interrupter valve It may be established in the absence of extraneous force on the reset stem 12 tending to overcome such bias. The essential structure of the control device I8, so far described, forms the subject matter of a copending application of Eskin et al., Serial No. 675,038, filed June '7, 19 16, and which has become Patent No. 2,603,509, issued July 15, 1952, and assigned to the assignee of the present invention.

In this invention, switching means are associated with the control device I8 for a purpose which will be apparent hereinafter. To this end, a switch housing 38 of insluating material is secured by screws 90 to the end wall of the end cap 56, there being a cover plate 92 interposed therebetween. The switch housing 88 is substantially rectangular in cross-section and has an axial opening 94 therein terminating in an internal annular flange 96. A pair of terminals 98 of angular form project through the annular flange 96 which is suitably recessed for such purpose and each carries one of a pair of contacts I65 positioned in the opening 94. The opposite side of the annular flange 96 is provided with a pair of arcuate channels I62 to receive a pair of conductors I84, I56 attached to the terminals 98. As will be apparent, the cover plate 92 serves to retain the conductors I04, I58 in position in the channels I02, and the terminals 98 in the recessed flange Q5, when the switch housing 88 is secured in position on the end cap 56.

The contact pair I00 is adapted for cooperation with a pair of relatively movable contacts IIO which are supported on a contact plate II2 carried by an insulating sleeve II4 for the reset stem it. Contact pressure is adjusted by the provision of a coil spring I94 which is operative between the contact plate I I2 and insulating collar H6 secured to the end of the reset stem 12 by a set screw H3 pro ecting axially therefrom. It will be apparent the reset stem 12 by pressure applied to the head of the screw IIi-i will serve not only to conduct the resetting operation described but also to cause concomitant closure of the switch contact pairs I00, H0.

The rectilinear 12 is eifected by movement of the reset stem the usual rotary manipulation of the handle or knob I20 oi the control device I8. Consequently, means are provided for translating rotation of the handle I20 into rectilinear movement of the reset stem 12. Such means take the form of an outer sleeve element I22 having a serrated flange I24 formed on the inner end thereof for engagement with a locking plate I26 having a complemental serrated aperture therein. A cover plate I28 extends over the flange I24 and the locking plate I26 and carries a pair of screws Ito by which the parts are secured to the end face of the switch housing 88. The outer sleeve element I22 is provided with a longitudinal slot I32 extending from adjacent the outer end thereof to the flange I24 thereon.

An inner sleeve element I34 is rotatably mounted in the outer sleeve element 22 and is provided with a substantially helical slot I35 terminating at its outer end opposite the outer end of the longitudinal slot I32. The inner end of the outer sleeve element I22 is provided with a pair of oppositely disposed lugs I38, conveniently struck up from the material of the flange I24, and serving to retain an annular cover plat:

I 40 in position between the flange I24 and the adjacent end of the inner sleeve element I34. The opposite end of the inner sleeve element I34 is secured by soldering or other means to a bushing I 42 which is also similarly secured to a tubular drive element I44 upon which the handle or knob I26 is carried in driving engagement. The rotary motion of the knob or handle I20 is transmitted to the inner sleeve element I34 by the tubular drive element M4 to rotate the inner sleeve element I34 relative to an operating stem within the tubular member I44 into operative engagement with the head of the screw H3 and carries a detent I48 interprojects through the slots I36 and I32 in the inner and outer sleeve elements I34, I22, respectively. It will be apparent that due to the helical nature of the slot I36, the rotary motion of the handle I 20 and the inner sleeve I34 will be translated into rectilinear movement of the reset nal slot I32 and only can occur.

Referring again the drawings, the preferred embodiment of the invention includes a ing ignition of the main burner Ill and being located in lighting proximity thereto. The pilot burner I59 is supplied with fuel by a conduit I52 which is connected to the control device I8 by way of an inlet port I 54 which communicates with the valve seat 22 intermediate the valve members 25 and 16. Thus, the pilot burner I 59 valve member 16 is engaged with the valve seat 22 immediately prior to the time that the cap nut 18 opens the valve member 26 during the resetting operation.

The electromagnetic device 24 is adapted to be energized by current generated by thermoelectric means responsive pilot burner I53. To this end, a tubular type b thermocouple I55 is shown as supported on a bracket I53 in unitary arrangement with the pilot burner I50 and located in heating proximity The lead 32 from 15 connected directly to the thermocouple I56 while the lead it therefrom is connected through a main switch I86 to the other terminal of the thermocouple I56. The main switch IE9 is preferably of the normally closed type having its operating member I 82 positioned to be engaged by a projection I64 on the operating element of the main fuel cock I S. The arrangement, as schematically shown in Fig. 1 of the drawings,

switch 1 50 through the connections described and interrupt the circuit of the electromagnet 24.

Electric ignition means are employed in this invention for producing a flame at the pilot burner I 56. To this end, an electric igniter I6 5 in the form of a coil of resistance wire is positioned in lighting proximity to the pilot burner I 50. The electrical system for the igniter I '65 includes a ballast unit I 68, a step-down transformer I and the switch contact pairs I00, IIIJ associated with the control device I3. The primary coil I12 of the transformer I10 has one end connected by wire I14 to one side of the power line while the other end of the primary the electromagnet 24 i coil I12 is connected by wire I04 to the terminal 98. The opposite side of the power supply is connected by wire I [I6 to the other terminal 98 thus completing the connection of the contact pair I00 in the primary circuit of the transformer I10. The secondary coil I15 of the transformer I III has one end connected by wire I15 to one end of the igniter I66, the opposite end of which is connected by wire IM to the opposite end of the transformer secondary I15. However, interposed in the latter wire I is the ballast unit I68, which is thus connected in series with the igniter I56 and the secondary coil I1 5.

The ballast unit I 98 consists in this embodiment of two coils I 82, I 8 connected in parallel circuit. The coil I82 is of. the variable resistance type having a relatively high temperature coefiicient of resistance and being subject to increased temperature upon passage of current therethrough. The resistor It l may be of the constant resistant type having no appreciable change in resistivity upon passage of current therethrough. As will be more apparent here- I16 in conjunction with a source of current supvoltage variations without deleterious effect upon the igniter I652.

The operation of the device is as follows: When the parts are positioned as shown in the drawings, no fuel can flow from the manifold I2 to the main burner It or the pilot burner I5Il and the igniter IE6 is deenergized. Operation of the main fuel fuel pipe It as far as as the valve member fit is engaged with the valve seat 2 2. During the ro tation of the main fuel cock It to open position, the main switch I SEI is closed so that the circuit from the thermocouple IE6 to the electromagnet I20 of the control device I8 is then rotated in a clockwise direction causing a rectilinear move-- ment to the left, as viewed in Fig. 2 of the drawings, of the operating stem I48 due to the translating action described. The existing operative engagement of the operating stem I 4G with the head of the screw I It causes the reset stem I2 to partake of the rectilinear movement and overcome the bias of the spring at. The connecting stem 14 is consequently moved to the left, as viewed in Fig. 2 of the drawing, and the interrupter valve member 16 becomes engaged with the valve seat 22. becomes engaged with the valve member and moves the latter away from the valve seat 22 against the bias of the spring 23 to reset the eleetromagnet 24 for a holding tioned that at a comparatively low voltage of volts in the primary coil I12, the igniter IE5 is energized sufiiciently to ignite the fuel flowing from the pilot burner I59. Should a voltage of volts in the primary coil I12 be present, then more current will flow through the ballast unit I68. It is apparof the ballast unit I68 remained constant, then the current at such comparatively high voltage would be sufficient to overload the igniter I56 and possibly cause its destruction. However, due to the use of the variable resistor I82 in the ballast unit I68, the resistance thereof increases with temperature and the current is consequently reduced to a safe value. When it is considered that a difference between high and low voltage input current of 2.4 amperes may be satisfactory whereas a difference of 3.2 amperes would be too great for practical usage, it is apparent that the provision of the ballast unit I68 is of importance in this application.

The fuel from the pilot burner I being ignited, the thermocouple I56 becomes heated and generates suificient current to energize the electromagnet 24. This operation takes but a few seconds and then the manual force applied to the handle I20 of the control unit I8 can be relieved. The bias of the coil spring 80 on the reset stem I2 causes retraction of this stern and such force is applied to the operating stem I46 which thereupon moves to the right as viewed in Fig. 2 of the drawing. This motion is translated by the sleeves I22, I34 and the detent I48 engaging with the slots therein into a rotary motion of the handle I20 in a counterclockwise direction to its initial position.

The retraction of the reset stem 12 causes opening of the contact pairs I00, III) and return of the flow interrupter valve 15 to its initial position out of engagement with the valve seat 22. As the valve member 26 is now held in open position due to energization of the electromagnet 24, the fuel from the main fuel pipe I4 flows to the main burner I0 and is ignited by the fiame from the pilot burner I50. The igniter IE6 is concurrently deenergized and remains in such condition during normal running conditions at the main burner I0. Thus the system is placed in steady state operating condition without further attention on the part of the operator.

Should the operator by mistake rotate the main fuel cock I6 from On to thereafter immediately to On position, then the control device I3 will automatically function to shut oif the flow of fuel to the main burner I0. Such operation will occur due to the immediate deenergization of the electromagnet 24 when the main switch I is operated to open position momentarily during rotation of the main fuel cock I6 to Ofi position. It will be apparent that without this automatic shut-off of the main burner I0, such repeated operation of the main fuel cock I6 while the thermocouple I56 remains heated might tend to cause an accumulation of main burner fuel which is undesirable. In the present embodiment of the invention, it is. necessary to reignite the pilot burner I50 before any fuel can flow to the main burner I0.

In the event that the flame at the pilot burner I50 becomes extinguished, then the thermocouple I56 will cool and cause deenergization of the electromagnet 24. The valve member 26 thereupon becomes reengaged with the valve seat 22 under bias of the spring 28 and shuts off flow oil fuel to both the main and pilot burners I0 and I56, respectively. A starting operation, as described, must then be conducted in order to place the system in running condition but further description of this operation is deemed unnecessary.

While the preferred embodiment of the invention described and shown herein includes a On position and pilot burner I50, it will be obvious that this burner could be dispensed with, if desired, and the thermocouple I56 and igniter I66 arranged for cooperation with the main burner I0 accordingly. In such event, the flow interrupter valve I6 would also be dispensed with as the function thereof would be unnecessary. This and other modifications in the general system and changes in the details of construction and arrangement of parts can be made within the scope of the appended claims without departing from the purview of the invention.

We claim:

1. An adapter for converting a fiame failure shut-off valve, having a reciprocable reset stem extending from a valve casing, into a combination ignition and fuel control device comprising, a hollow switch housing of insulating material adapted to be secured to the valve casing and to enclose the outer end of the reset stem, a rotatable handle carried by said housing, an operating stem within said housing extending from adjacent said handle and adapted to engage the outer end of the reset stem, first electrical contact means carried on an inner wall of said housing and adapted for connection in the energizing circuit of an electric igniter, second electrical contact means engageable with said first contact means, means for supporting said second contact means and connecting the same to the 'reset stem for movement therewith, and cam means operatively connecting said handle and said operating stem for translating rotation of said handle into rectilinear movement of said operating stem for imparting resetting movement to the reset stern and moving said second contact means into engagement with said first contact means.

2. Apparatus as claimed in claim 1 wherein said second contact supporting means comprises a tubular member of insulating material adapted to receive the outer end of the reset stem.

3. Apparatus as claimed in claim 2 wherein said second contact means comprises an apertured plate slidably mounted on said tubular member, and an override spring encircling said tubular member and engageable with said plate for biasing the same toward said first contact means.

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